There are two Erg Pots in this dungeon - The first can be found in Area 1, just on the left at the beginning. The second can be found in Area 2, above the stairs in the last room. You can destroy it by using spear.
There is one ore deposits in this battle. Area 3, Path 2, located on the right side as soon as you walk into the last room where the Five Spider Brothers show up under the arch in the wall.
Trivia
In Mabinogi: Fantasy Life, there is a similar dungeon to The Five Spider Brothers in which it hosted three different colored Giant Spiders as the end boss.